The Optimodyne jingle was stuck in Sam's head again.

  You've got the drive, we've got the gear—

  Optimodyne! Make your future clear!

  It played during commercial breaks. It played between podcasts. It played from the speakers at CVS while she bought acne cream, a cheerful earworm burrowing into her brain like a parasitic wasp laying eggs.

  Sam killed the engine in the school parking lot and sat there for a moment, hands still on the wheel of her mom's old Honda. Through the windshield, Northwood High gleamed in the weak November sun. Perfectly manicured hedges. Fresh paint on the columns. A banner stretched across the main entrance: CLASS OF 3030: BUILDING YOUR FUTURE TODAY.

  Underneath it, Kevin Chen was holding his own severed arm.

  He wasn't screaming. He wasn't even upset. He just stood there with a perplexed frown, looking down at the limb cradled in his remaining hand like it was a smartphone with a cracked screen.

  "Oh, come on," Kevin muttered. "I just got this reattached on Tuesday."

  Sam got out of the car. Her sneakers crunched on the gravel. Kevin looked up and offered a sheepish grin, blood soaking into the cuff of his Northwood High hoodie.

  "Hey, Sam. Can you grab the door?"

  She grabbed the door.

  "Thanks." Kevin walked past her into the building, arm still in his hand, leaving a dotted line of crimson on the linoleum. "Mr. Henderson's gonna kill me. I have a calc quiz third period."

  The door swung shut. Sam stood in the entryway, watching him disappear down the hallway, his blood already being smeared into a pink gloss by the janitor's mop.

  The janitor hummed the Optimodyne jingle as he worked.

  A year ago, Sam would have categorized Kevin's arm situation as an emergency.

  A year ago, the school would have cancelled classes. There would have been an assembly. Grief counselors with boxes of tissues. A moment of silence.

  Now, Kevin was just going to be late for calc.

  Sam walked to her locker. The hallways were busy with the usual pre-first-bell chaos: slamming lockers, shouted greetings, the smell of instant coffee and strawberry vape. But there was a new texture to the chaos. A different frequency.

  Mariana Vasquez clicked past on legs that were no longer legs. They were carbon-fiber blades, curved like parentheses, sleek and matte black. She moved with a spring-loaded grace, her natural feet replaced by something designed for pure forward momentum. The blades chirped against the tile with every step. Chirp. Chirp. Chirp.

  "Sam!" Mariana's face was bright, unclouded by the fact that her lower half had been traded for sporting goods. "Did you see the email? Coach says with the new setup I'm shaving three seconds off my mile. Three seconds, Sam. That's the difference between recruited and walk-on at Division Three."

  "Great," Sam said. "How do they feel?"

  Mariana paused. The smile flickered, just for a moment.

  "Phantom limb thing is still there," she admitted. "Sometimes I wake up and I can feel my feet, you know? Like they're still there. Itching. But when I look down, it's just..." She gestured at the blades. "Optimodyne says that's normal. Part of the adjustment period."

  "Part of the adjustment period," Sam repeated.

  "Yeah. Hey, did you get your consultation yet? My parents keep asking if you're gonna—"

  "I'm good."

  "Oh." Mariana's face did something complicated. Pity? Confusion? The particular look people get when you tell them you're not on Instagram. "Okay. Well. Let me know if you want to talk about it. It's a big decision."

  Chirp. Chirp. Chirp. She was gone, rounding the corner toward the gymnasium, her blades carrying her toward a future that didn't include feet.

  Sam opened her locker.

  A brochure fluttered out.

  Glossy paper. Bright colors. A family smiling on a pristine lawn, their faces radiant with the particular joy of people who have never experienced a complication. The mother's hands were normal. The father's hands were normal. The teenager in the middle—could have been any teenager, could have been Sam—held up an acceptance letter with fingers that gleamed faintly metallic in the staged sunlight.

  THE FULL RIDE PACKAGE

  Why be well-rounded when you can BE the circle?

  Ask your parents about Optimodyne today.

  Sam crumpled it and threw it back into the locker.

  Someone behind her laughed.

  "You know those things multiply, right? You throw one away, three more grow in its place. Like hydras. But with more stock photos."

  Jasper Reyes leaned against the lockers, arms crossed, messenger bag slung across his chest. He was one of the few people at Northwood who still looked like a person. Two arms. Two legs. Face unmodified. They'd had AP Euro together junior year and bonded over a shared hatred of group projects.

  "Jasper." She felt something loosen in her chest. "You're normal."

  "Debatable." He pushed off the lockers and fell into step beside her as she headed for class. "But yeah, no, I still have all my original factory-issue parts. My mom cried when I told her I wasn't doing it. Like, actual tears. Said I was throwing away my future."

  "What did you say?"

  "I said if my future depends on replacing my pancreas with a graphing calculator, maybe the future sucks."

  Sam laughed. It came out weird—rusty, like she hadn't used it in a while.

  They walked past the senior bulletin board. It was covered in Optimodyne ads. Also college pennants, scholarship deadlines, a flyer for a SAT prep course that met in a basement and required a parental waiver. But mostly the ads. The same smiling family. The same taglines. Unlock your potential. Literally.

  A girl sat cross-legged on the floor beneath the bulletin board, her back against the wall. She was drawing in a sketchbook. Her fingers moved with fluid precision, pencil dancing across the page.

  Sam stopped.

  The author's content has been appropriated; report any instances of this story on Amazon.

  The girl's fingers weren't fingers. They were brushes. Thin, tapered, bristled at the tips. They flexed and bent like organic things, which they were—grown in a vat, Optimodyne's literature explained, cultured from the student's own cells and then shaped for maximum artistic output. The bristles were dark with ink. Her hands left small black smudges on everything they touched.

  She looked up. Smiled. Her face was pretty in an unremarkable way, except for the faint dark stains around her cuticles.

  "Hey," the girl said. "I like your backpack."

  Sam looked down at her backpack. It was blue. She'd had it since ninth grade.

  "Thanks," she said. "I like your... hands."

  The girl looked at her hands. Turned them over. The brushes caught the fluorescent light.

  "Yeah," she said. "They're a pain to wash. But my portfolio is insane now. Like, actually insane. I'm doing a series on industrial decay. The texture work is—" She gestured, unable to find the words, leaving a small black arc on the air. "You know."

  Sam didn't know.

  "Come on," Jasper muttered. "We're gonna be late."

  They left the girl on the floor, drawing again, her brush-fingers moving in small, precise strokes.

  First period was English. Mr. Malloy was forty-seven years old and looked it, a holdout from the before-times who still wore tweed jackets with elbow patches and assigned essays on symbolism in The Great Gatsby. He was also, Sam suspected, deeply terrified of his students.

  "Okay, folks," he said, perching on the edge of his desk like a bird ready to take flight. "College application essays. We're going to do a peer review workshop today. Everyone trade with a partner and read each other's drafts."

  A boy in the front row raised his hand. His name was Derek. He had new eyes.

  Sam tried not to stare. She'd seen them in the Optimodyne catalog—the Scholar's Visual Cortex, retail $47,000, insurance usually covered sixty percent if you could prove academic necessity. Derek's natural eyes had been removed and replaced with something that looked like a GoPro had mated with a spider. Multiple lenses. Faint red light pulsing in the depths. When he blinked, the lenses clicked.

  "Mr. Malloy," Derek said. "My essay is in visual format. The admissions board at MIT prefers multi-modal submissions."

  Mr. Malloy swallowed. "Right. Of course. Um. Does anyone have—can anyone read visual format?"

  No one raised their hands.

  "I can project it," Derek offered. "If that helps."

  He didn't wait for an answer. The lenses in his eyes glowed brighter. Suddenly, images flickered on the back wall—a slideshow, beamed directly from Derek's optic nerves to the whiteboard like some kind of organic projector. Schematics. Code. A photo of Derek shaking hands with a man in a lab coat.

  "I see the world in systems," Derek's voice narrated, coming from his mouth but also somehow from everywhere. "My passion for engineering began when I was six years old and took apart my mother's blender."

  Sam's stomach turned.

  Jasper, sitting next to her, leaned over. "He took apart his mother's blender," he whispered. "And then he took apart his mother's blender budget. And then he took apart his mother's health insurance to pay for the eyes."

  "Stop," Sam whispered back, but she was smiling.

  The slideshow continued. Derek's life, rendered in high-definition, projected directly from his skull. When it finished, the class applauded. Derek's lenses clicked in what might have been satisfaction.

  Mr. Malloy looked slightly ill.

  "Great," he said. "That was... great. Anyone else? Anyone with a... traditional essay?"

  Sam's hand was halfway up when the fluorescent lights flickered.

  Then they went out.

  Then the emergency alarms started—not the fire drill, but something else. A low whoop-whoop-whoop that Sam had never heard before. Red lights began to spin in the corners of the room.

  "Code Silver," someone said. "That's Code Silver."

  The room went very quiet.

  Code Silver meant a student had gone into systemic rejection. It meant the body was fighting the modifications. It meant that somewhere in this building, a teenager's immune system had decided that the carbon-fiber legs or the brush-fingers or the GoPro eyes were enemies to be destroyed.

  Mr. Malloy stood up. "Everyone stay—"

  He didn't finish. The door banged open.

  It was Kevin Chen.

  His face was gray. His remaining hand clutched his shoulder, where the reattached arm had been. The arm was gone again—not severed this time, but something worse. The skin was peeling away in sheets, revealing something dark and fibrous underneath. The flesh was dissolving, sloughing off like overcooked chicken, dripping onto the floor in wet chunks.

  "Help," Kevin said. His voice was very small. "It's happening again. They said the immunosuppressants would—they said—"

  He took a step forward and collapsed.

  The wet sound he made when he hit the floor was not a sound that human bodies are supposed to make.

  Someone screamed. Sam wasn't sure if it was her.

  Mr. Malloy moved faster than she'd ever seen him move, grabbing the phone on his desk, stabbing at numbers. The red lights kept spinning. The alarms kept whooping. Kevin lay on the floor, twitching, his body continuing its slow collapse in real time.

  Jasper grabbed Sam's arm.

  "Don't look," he said.

  She looked anyway.

  Kevin's eyes were open. They were still human eyes—he'd never replaced those. They looked at Sam with an expression she couldn't quite read. Pain? Fear? Or something worse: the dawning realization that the brochure had lied, that the warranty had expired, that the future he'd paid for with his own flesh was eating him from the inside out.

  "Sam," he whispered.

  Then his jaw unhinged and something dark poured out.

  They evacuated to the football field.

  Sam sat in the bleachers, shaking, watching as a team of people in white hazmat suits carried Kevin out on a stretcher. He was covered entirely in plastic. The only visible part of him was one hand—the one that had stayed attached—dangling over the edge, fingers twitching with random nerve firings.

  "Is he dead?" Mariana Vasquez asked. She'd taken off her blades, sitting in sweatpants that ended abruptly at the carbon-fiber stumps. Her face was pale but curious, like she was asking about a test grade.

  "I don't know," Sam said.

  "Optimodyne has a ninety-seven percent success rate on reattachment procedures," Derek said. His multiple lenses were all focused on the stretcher, recording, cataloging. "Kevin's case was statistically unusual."

  "Statistically unusual," Jasper repeated. "He melted."

  "The body rejects foreign material sometimes. It's a known risk."

  "Known risk," Jasper said. "Cool. Cool cool cool."

  A woman in an Optimodyne polo shirt appeared at the edge of the field, holding a clipboard and a microphone. She had the perky energy of a game show host. Her hands were normal—probably a corporate decision, Sam thought. No one wants to be sold body modification by someone who's visibly modified.

  "Attention, Northwood students!" Her voice boomed from portable speakers. "We know today's incident was scary. But don't let fear hold you back from your dreams! Remember, Optimodyne stands behind every procedure with our industry-leading Lifetime Commitment Guarantee—which includes, yes, complications management! Talk to your parents! Talk to your guidance counselor! And remember—"

  She smiled. The smile was enormous.

  "You've got the drive, we've got the gear."

  A few students cheered. Mariana Vasquez actually clapped.

  Sam sat in the bleachers, watching Kevin's stretcher disappear into an ambulance with no lights, no sirens, just the quiet efficiency of a system designed to clean up its own messes.

  Jasper sat beside her.

  "My mom's gonna bring up the pancreas again tonight," he said. "She's gonna be like, 'See? If you'd just gotten the SmartSpleen, you'd be safe. Kevin was a fool. He got the cheap package.'"

  "Your mom wants you to get a SmartSpleen?"

  "She saw a commercial. It tracks your blood alcohol content and texts your parents if you drink."

  Sam stared at him.

  "Teenagers don't even drink from their spleen, Jasper. That's not—that's not how alcohol works."

  "Try telling her that. She's already picked out the payment plan."

  The ambulance pulled away. Students began to drift back toward the building, conversation returning to normal topics: college applications, weekend plans, whose turn it was to pick up Starbucks before second period.

  Sam's phone buzzed.

  A text from her mom: Honey saw what happened at school on the news. So scary! Anyway Dad and I were thinking maybe we should have that talk about Optimodyne. Nothing major! Just a consultation. To see options. Love you! ??

  Sam looked at the phone for a long time.

  Then she looked at the school. At the banner: BUILDING YOUR FUTURE TODAY. At the kids filing back inside on carbon-fiber legs and brush-tip fingers and camera-lens eyes. At the Optimodyne representative still standing on the field, handing out brochures to freshmen who hadn't learned to be afraid yet.

  Jasper followed her gaze.

  "You okay?" he asked.

  Sam thought about it.

  "No," she said. "But I have to turn in my calc homework, so."

  She stood up.

  Her phone buzzed again. Another text from her mom: The consultant says they have a special going on the Scholar's Cortex this month. Bundle it with the Athletic Foundation and you save 15%! Think of the essay you could write!

  Sam put the phone in her pocket without responding.

  The Optimodyne jingle was still stuck in her head.

  You've got the drive, we've got the gear—

  Optimodyne! Make your future clear!

  She walked back toward the building, past a freshman who was crying quietly while her mother filled out consent forms on a clipboard, past a kid showing off his new titanium knuckles to a group of admiring juniors, past the spot on the linoleum where Kevin Chen had melted.

  The janitor had already mopped it up.

  He was humming as he worked.